A heat-insulating and heat-preserving film, its preparation method and application

Abstract

The present invention discloses a heat-insulating and heat-preserving film, its preparation method and application. The heat-insulating and heat-preserving film includes a light conversion layer, a heat-insulating layer disposed on one side of the light conversion layer, and a heat-preserving layer disposed on the other side of the light conversion layer; the light conversion layer includes a light conversion agent, and the light conversion agent includes a blue light conversion agent and a red light conversion agent; the heat-insulating layer includes a heat-insulating material; the heat-preserving layer includes a heat-preserving material. The heat-insulating and heat-preserving film of the present invention can regulate the temperature in the greenhouse, enable plants to grow at an appropriate temperature, promote their growth and development, and improve the quality of fruits.

Description

Technical Field

[0001] The present invention relates to the technical field of materials, and particularly relates to a heat-insulating and heat-preserving film, a preparation method thereof, and an application thereof. Background Art

[0002] A light conversion film is a film material that can convert or adjust the wavelength of light and is commonly used in fields such as agriculture, photovoltaics, and lighting. In agriculture, light conversion films are mainly used as greenhouse covering materials. By converting ultraviolet light or infrared light that is not conducive to plant growth into visible light that is conducive to photosynthesis, the light efficiency utilization rate of crops can be improved, promoting growth and increasing yields.

[0003] The multi-layer coextrusion technology is a method for manufacturing high-performance agricultural films. By coextruding multiple polymer materials with different functions to form a multi-layer structure, various superior properties can be imparted to the agricultural film. Through different combinations of materials at each layer, functions such as anti-ultraviolet, heat preservation, light transmission, anti-fogging, and anti-aging can be achieved. Each layer of material optimizes its own properties, such as the weather resistance of the outer layer, the strength of the middle layer, and the heat preservation of the inner layer, thereby overall improving the performance of the film. Compared with single-layer films, multi-layer coextruded films can significantly improve the functions and service life of the film without significantly increasing costs.

[0004] The heat insulation performance of agricultural films is crucial for agricultural production, especially for greenhouse cultivation. Heat-insulating agricultural films can effectively control the temperature inside the greenhouse, reduce heat loss or excessive heat accumulation, prevent overheating during the day and rapid heat dissipation at night, and thus provide a more suitable growth environment for crops. In greenhouse cultivation, heat-insulating films can reduce heat accumulation during the day, avoid the harm of high temperature to crops, and maintain a certain temperature at night.

[0005] Heat preservation is an important function in agricultural production, especially in greenhouse and greenhouse cultivation. The heat preservation performance directly affects the growth environment and yield of crops. Agricultural films can reduce the heat dissipation from the greenhouse to the outside and maintain the temperature inside the greenhouse. In seasons with low temperatures, agricultural films with good heat preservation performance can block the entry of cold air from the outside and maintain a stable internal temperature, enabling plants to continue growing in winter. The heat dissipation in the greenhouse is mainly caused by the far-infrared radiation effect. The wavelength of the ground infrared radiation is mainly in the range of 7-14 μm. The heat preservation layer can effectively block the radiation dissipation in this wavelength range, thereby keeping the temperature in the greenhouse.

[0006] However, the existing agricultural films have too single heat insulation and heat preservation performance and cannot meet the growth needs of plants in areas with large temperature differences between day and night. Summary of the Invention

[0007] The present invention aims to at least solve one of the above technical problems existing in the prior art. For this reason, the object of the present invention is to provide a heat-insulating and heat-preserving film, a preparation method thereof, and an application thereof.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] In a first aspect of the present invention, there is provided a heat-insulating and heat-preserving film, which includes a light conversion layer, a heat-insulating layer provided on one side of the light conversion layer, and a heat-preserving layer provided on the other side of the light conversion layer; the light conversion layer includes a light conversion agent, and the light conversion agent includes a blue light conversion agent and a red light conversion agent; the heat-insulating layer includes a heat-insulating material; and the heat-preserving layer includes a heat-preserving material.

[0010] In the present invention, the film has excellent light conversion ability, converting ultraviolet light and yellow-green light in sunlight into blue light and red light required for plant photosynthesis, and promoting plant morphogenesis (such as leaf morphology, stem elongation, etc.) and bud germination, flower bud differentiation, and the flowering process. Secondly, the heat-insulating layer provided on one side of the light conversion layer can block excessive heat from entering the greenhouse during the day in summer, preventing the growth of plants from being inhibited due to excessive high temperature. The heat-preserving layer provided on the other side of the light conversion layer can reduce the adverse effects on plants caused by the relatively low temperature at night in areas with large day-night temperature differences.

[0011] In some embodiments of the present invention, the blue light conversion agent includes an aluminate light conversion agent, such as BaMgAl 10 O 17 :Eu 2+ .

[0012] In some embodiments of the present invention, the red light conversion agent includes MS:Eu, Re; wherein, M is selected from at least one of Ca, Sr, Ba, Zn, Fe, Mg, Ti; and Re is selected from at least one of Ce, Dy, Sm, Yb, Tb.

[0013] In some embodiments of the present invention, the addition amounts of the blue light conversion agent and the red light conversion agent in the light conversion layer respectively account for 0.01% - 10% of the mass of the light conversion layer.

[0014] In some embodiments of the present invention, the heat-insulating material includes at least one of titanium dioxide, tin oxide, aluminum oxide, zirconium oxide, and magnesium oxide, and such materials have a low thermal conductivity.

[0015] In some embodiments of the present invention, the size of the heat-insulating material is 10 - 150 nm; the addition amount of the heat-insulating material accounts for 0.5 - 20% of the mass of the heat-insulating layer.

[0016] In some embodiments of the present invention, the heat-preserving material includes at least one of aluminum silicate, tourmaline, and hydrotalcite.

[0017] In some embodiments of the present invention, the addition amount of the heat-preserving material accounts for 0.5 - 20% of the mass of the heat-preserving layer.

[0018] In some embodiments of the present invention, the thickness of the heat insulation layer is 5 - 200 μm.

[0019] In some embodiments of the present invention, the thickness of the light conversion layer is 1 - 150 μm.

[0020] In some embodiments of the present invention, the thickness of the heat preservation layer is 1 - 180 μm.

[0021] In some embodiments of the present invention, each layer of the heat insulation and heat preservation film further contains a matrix resin and an auxiliary agent respectively.

[0022] In some embodiments of the present invention, the matrix resin includes at least one of polyethylene, nylon, polyvinyl alcohol, polypropylene, ethylene propylene diene monomer rubber, CTC resin, and maleic anhydride.

[0023] In some embodiments of the present invention, the auxiliary agent includes at least one of a lubricant, a light stabilizer, an antioxidant, a solubilizer, and a coupling agent.

[0024] In the second aspect of the present invention, a method for preparing the heat insulation and heat preservation film is provided, including the following steps:

[0025] Carry out three - layer co - extrusion on the premixes of the heat insulation layer, the light conversion layer, and the heat preservation layer to obtain the heat insulation and heat preservation film.

[0026] In some embodiments of the present invention, the matrix resin, the heat insulation material, and the auxiliary agent are fully mixed evenly to obtain a heat insulation premix.

[0027] In some embodiments of the present invention, the matrix resin, the light conversion agent, and the auxiliary agent are fully mixed evenly to obtain a light conversion premix.

[0028] In some embodiments of the present invention, the matrix resin, the heat preservation material, and the auxiliary agent are fully mixed evenly to obtain a heat preservation premix.

[0029] In the third aspect of the present invention, the application of the heat insulation and heat preservation film in agricultural greenhouses is proposed.

[0030] The beneficial effects of the present invention are:

[0031] In the present invention, the film adopts a multi-layer co-extrusion technology. The outer layer is a heat-insulating layer, the middle layer is a light-converting layer, and the inner layer is a heat-preserving layer. Under this structure, the film has excellent light-converting ability, converting ultraviolet light and yellow-green light in sunlight into blue light and red light required for plant photosynthesis, promoting plant morphogenesis (such as leaf morphology, stem elongation, etc.) and the germination of buds, flower bud differentiation, and the flowering process. Secondly, the outer layer is a heat-insulating layer, which can block excessive heat from entering the greenhouse during the day in summer, preventing plants from being inhibited in growth due to excessive high temperature. Finally, the inner layer of the film is set as a heat-preserving layer, which can reduce the adverse effects on plants caused by the relatively low temperature at night in areas with large temperature differences between day and night. For plant growth, high temperature during the day will inhibit plant photosynthesis, accelerate plant transpiration, and inhibit growth and development, which will lead to a reduction in the nutritional components of plants or their fruits, a deterioration in taste, premature ripening, and stagnant growth. A relatively low temperature at night will reduce the metabolic rate of plants, resulting in slower cell division and expansion, thereby inhibiting the growth of plants and fruits, leading to poor growth and development of plants and fruits.

[0032] The heat-insulating and heat-preserving film of the present invention can regulate the temperature in the greenhouse, enabling plants to grow at an appropriate temperature, promoting their growth and development, and improving the quality of fruits. Brief Description of the Drawings

[0033] Figure 1 It shows the structure and actual application scenario of the heat-insulating and heat-preserving film of the present invention. Detailed Description of the Invention

[0034] The content of the present invention will be further described in detail below through specific embodiments. The raw materials, reagents, or devices used in the embodiments and comparative examples can be obtained from conventional commercial channels or can be obtained by existing technical methods without special instructions. Unless otherwise specified, the test or measurement methods are all conventional methods in the art.

[0035] In the following embodiments or comparative examples, the preparation method of the film all adopts the co-extrusion method.

[0036] Figure 1 It shows the structure and actual application scenario of the heat-insulating and heat-preserving film of the present invention.

[0037] Example 1

[0038] In this example, a heat-insulating and heat-preserving film was prepared. The specific process is as follows:

[0039] The heat-insulating and heat-preserving film comprises a heat-insulating layer, a light conversion layer and a heat-preserving layer; wherein the heat-insulating layer is the outer layer, the light conversion layer is the middle layer, and the heat-preserving layer is the inner layer; the heat-insulating layer comprises a heat-insulating material and a carrier resin, and this layer of heat-insulating premix is composed of 2% titanium dioxide and polyethylene, with a thickness of 30 μm; the light conversion layer comprises a red-light and blue-light light conversion carrier resin layer, and this layer of light conversion carrier resin layer is respectively composed of polyethylene, a sulfide red-light light conversion agent and an aluminate light conversion agent, the addition amounts of the red-light and blue-light light conversion agents are respectively 1%, and the thickness is 20 μm; the heat-preserving layer comprises a heat-preserving material and a carrier resin, and this layer of heat-preserving premix is composed of 2% aluminum silicate and polyethylene, with a thickness of 30 μm; the total thickness of the light conversion film is 80 μm.

[0040] Example 2

[0041] In this example, a heat-insulating and heat-preserving film was prepared, and the specific process was as follows:

[0042] The heat-insulating and heat-preserving film comprises a heat-insulating layer, a light conversion layer and a heat-preserving layer; wherein the heat-insulating layer is the outer layer, the light conversion layer is the middle layer, and the heat-preserving layer is the inner layer; the heat-insulating layer comprises a heat-insulating material and a carrier resin, and this layer of heat-insulating premix is composed of 4% tin oxide and nylon, with a thickness of 40 μm; the light conversion layer comprises a red-light and blue-light light conversion carrier resin layer, and this layer of light conversion carrier resin layer is respectively composed of polyethylene, a sulfide red-light light conversion agent and an aluminate light conversion agent, the addition amounts of the red-light and blue-light light conversion agents are respectively 1%, and the thickness is 50 μm; the heat-preserving layer comprises a heat-preserving material and a carrier resin, and this layer of heat-preserving premix is composed of 2% aluminum silicate and polyethylene, with a thickness of 30 μm; the total thickness of the light conversion film is 120 μm.

[0043] Example 3

[0044] In this example, a heat-insulating and heat-preserving film was prepared, and the specific process was as follows:

[0045] The heat-insulating and heat-preserving film comprises a heat-insulating layer, a light conversion layer and a heat-preserving layer; wherein the heat-insulating layer is the outer layer, the light conversion layer is the middle layer, and the heat-preserving layer is the inner layer; the heat-insulating layer comprises a heat-insulating material and a carrier resin, and this layer of heat-insulating premix is composed of 10% titanium dioxide and polyethylene, with a thickness of 30 μm; the light conversion layer comprises a red-light and blue-light light conversion carrier resin layer, and this layer of light conversion carrier resin layer is respectively composed of polyethylene, a sulfide red-light light conversion agent and an aluminate light conversion agent, the addition amounts of the red-light and blue-light light conversion agents are respectively 2%, and the thickness is 20 μm; the heat-preserving layer comprises a heat-preserving material and a carrier resin, and this layer of heat-preserving premix is composed of 1% aluminum silicate and polyethylene, with a thickness of 30 μm; the total thickness of the light conversion film is 80 μm.

[0046] Example 4

[0047] In this example, a heat-insulating and heat-preserving film was prepared, and the specific process was as follows:

[0048] The heat-insulating and heat-preserving film comprises a heat-insulating layer, a light-converting layer and a heat-preserving layer; wherein the heat-insulating layer is the outer layer, the light-converting layer is the middle layer, and the heat-preserving layer is the inner layer; the heat-insulating layer comprises a heat-insulating material and a carrier resin, and this layer of heat-insulating premix is composed of 1% titanium dioxide and polyethylene, with a thickness of 30 μm; the light-converting layer comprises a red-light and blue-light light-converting carrier resin layer, and this layer of light-converting carrier resin layer is respectively composed of polyethylene, a sulfide red-light light-converting agent and an aluminate light-converting agent, and the addition amounts of the red-light and blue-light light-converting agents are respectively 2%, with a thickness of 20 μm; the heat-preserving layer comprises a heat-preserving material and a carrier resin, and this layer of heat-preserving premix is composed of 15% aluminum silicate and polyethylene, with a thickness of 30 μm; the total thickness of the light-converting film is 80 μm.

[0049] Comparative Example 1

[0050] A film was prepared in this comparative example, and the specific process was as follows:

[0051] This film comprises a light-converting layer and a heat-preserving layer; wherein the light-converting layer is the outer layer and the heat-preserving layer is the inner layer; the light-converting layer comprises red-light, blue-light light-converting agents, a heat-insulating material and a carrier resin, and this layer of carrier resin layer is respectively composed of polyethylene, a sulfide red-light light-converting agent, an aluminate light-converting agent and titanium dioxide, and the addition amounts of the red-light and blue-light light-converting agents are respectively 1%, the addition amount of titanium dioxide is 2%, with a thickness of 20 μm; the heat-preserving layer comprises a heat-preserving material and a carrier resin, and this layer of heat-preserving premix is composed of 2% aluminum silicate and polyethylene, with a thickness of 50 μm; the total thickness of the light-converting film is 70 μm.

[0052] Comparative Example 2

[0053] A film was prepared in this comparative example, and the specific process was as follows:

[0054] This film comprises a heat-insulating layer and a light-converting layer; wherein the heat-insulating layer is the outer layer and the light-converting layer is the inner layer; the heat-insulating layer comprises a heat-insulating material and a carrier resin, and this layer of heat-insulating premix is composed of 2% titanium dioxide and polyethylene, with a thickness of 30 μm; the light-converting layer comprises a red-light, blue-light light-converting and heat-preserving material carrier resin layer, and this layer of light-converting carrier resin layer is respectively composed of polyethylene, a sulfide red-light light-converting agent, an aluminate light-converting agent and 2% aluminum silicate, and the addition amounts of the red-light and blue-light light-converting agents are respectively 1%, with a thickness of 50 μm; the total thickness of the light-converting film is 80 μm.

[0055] Comparative Example 3

[0056] A film was prepared in this comparative example, and the specific process was as follows:

[0057] The film includes a light conversion layer and a heat preservation layer; among them, the light conversion layer is the outer layer and the heat preservation layer is the inner layer; the light conversion layer includes a red and blue light conversion carrier resin layer, and this light conversion carrier resin layer is composed of polyethylene, a sulfide red light conversion agent, and an aluminate light conversion agent respectively. The addition amounts of the red and blue light conversion agents are 2% respectively, and the thickness is 20 μm; the heat preservation layer includes a heat preservation material and a carrier resin, and this heat preservation premix is composed of 2% aluminum silicate and polyethylene, and the thickness is 30 μm; the total thickness of the light conversion film is 50 μm.

[0058] Comparative Example 4

[0059] In this comparative example, a film was prepared. The specific process is as follows:

[0060] The film includes a heat insulation layer and a light conversion layer; among them, the heat insulation layer is the outer layer and the light conversion layer is the inner layer; the heat insulation layer includes a heat insulation material and a carrier resin, and this heat insulation premix is composed of 2% tin oxide and polyethylene, and the thickness is 30 μm; the light conversion layer includes a red and blue light conversion carrier resin layer, and this light conversion carrier resin layer is composed of polyethylene, a sulfide red light conversion agent, and an aluminate light conversion agent respectively. The addition amounts of the red and blue light conversion agents are 1% respectively, and the thickness is 20 μm; the total thickness of the light conversion film is 50 μm.

[0061] Comparative Example 5

[0062] In this comparative example, a film was prepared. The specific process is as follows:

[0063] The film includes a heat insulation and heat preservation layer and a light conversion layer; among them, the heat insulation and heat preservation layer is the outer layer and the light conversion layer is the inner layer; the heat insulation and heat preservation layer includes a heat insulation material, a heat preservation material and a carrier resin, and this heat insulation premix is composed of 2% titanium dioxide, 2% aluminum silicate and polyethylene, and the thickness is 60 μm; the light conversion layer includes a red and blue light conversion carrier resin layer, and this light conversion carrier resin layer is composed of polyethylene, a sulfide red light conversion agent, and an aluminate light conversion agent respectively. The addition amounts of the red and blue light conversion agents are 1% respectively, and the thickness is 20 μm; the total thickness of the light conversion film is 80 μm.

[0064] Comparative Example 6

[0065] In this comparative example, a film was prepared. The specific process is as follows:

[0066] The film includes a light conversion layer and a heat insulation and heat preservation layer; among them, the light conversion layer is the outer layer and the heat insulation and heat preservation layer is the inner layer; the light conversion layer includes a red and blue light conversion carrier resin layer, and this light conversion carrier resin layer is composed of polyethylene, a sulfide red light conversion agent, and an aluminate light conversion agent respectively. The addition amounts of the red and blue light conversion agents are 1% respectively, and the thickness is 20 μm; the heat preservation layer includes a heat insulation and heat preservation material and a carrier resin, and this heat preservation premix is composed of 2% titanium dioxide, 2% aluminum silicate and polyethylene, and the thickness is 60 μm; the total thickness of the light conversion film is 80 μm.

[0067] Comparative Example 7

[0068] In this comparative example, a film was prepared. The specific process was as follows:

[0069] The film included a light conversion layer, without setting a heat insulation layer and a heat preservation layer, that is, this layer only had resin and no heat insulation and heat preservation materials; the heat insulation layer only included a carrier resin, and the heat insulation premix of this layer was composed of polyethylene with a thickness of 30 μm; the light conversion layer included a red light and blue light conversion carrier resin layer, and this layer of light conversion carrier resin layer was respectively composed of polyethylene, a sulfide red light conversion agent, and an aluminate light conversion agent. The addition amounts of the red light and blue light conversion agents were both 1%, and the thickness was 20 μm; the heat preservation layer only included a carrier resin, and the heat preservation premix of this layer was composed of polyethylene with a thickness of 30 μm; the total thickness of the light conversion film was 80 μm.

[0070] Test Example 1

[0071] The films prepared in the examples and comparative examples were subjected to performance tests in areas with large day-night temperature differences. Specifically, the films were applied in agricultural greenhouses, and the temperature inside the greenhouses was measured at specific time points. The results are shown in Table 1.

[0072] Table 1

[0073]

[0074] The above embodiments are preferred embodiments of the present invention. However, the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. An agricultural greenhouse heat-insulating and heat-preserving film, characterized in that: It includes a light conversion layer, a heat insulation layer disposed on one side of the light conversion layer, and a heat preservation layer disposed on the other side of the light conversion layer; the light conversion layer includes a light conversion agent, and the light conversion agent includes a blue light conversion agent and a red light conversion agent; the heat insulation layer includes a heat insulation material; the heat preservation layer includes a heat preservation material; the heat insulation layer is the outer layer, the light conversion layer is the middle layer, and the heat preservation layer is the inner layer; The blue light conversion agent includes an aluminate light conversion agent; the red light conversion agent includes MS:Eu, Re; wherein, M is selected from at least one of Ca, Sr, Ba, Zn, Fe, Mg, Ti; Re is selected from at least one of Ce, Dy, Sm, Yb, Tb; The heat insulation material is titanium dioxide or tin oxide; the size of the heat insulation material is 10 - 150 nm; the addition amount of the heat insulation material accounts for 2 - 10% of the mass of the heat insulation layer; The heat preservation material is aluminum silicate; the addition amount of the heat preservation material accounts for 2 - 15% of the mass of the heat preservation layer; The thickness of the heat insulation layer is 30 - 40 μm; the thickness of the light conversion layer is 20 - 50 μm; the thickness of the heat preservation layer is 30 μm.

2. The heat-insulating and heat-preserving film for agricultural greenhouses according to claim 1, wherein: The blue light converting agent includes BaMgAl 10 O 17 :Eu 2+ .

3. The heat-insulating and heat-preserving film for agricultural greenhouses according to claim 1, wherein: The addition amounts of the blue light conversion agent and the red light conversion agent in the light conversion layer respectively account for 0.01% - 10% of the mass of the light conversion layer.

4. The heat insulation and heat preservation film for agricultural greenhouses according to claim 1, wherein: Each layer of the heat insulation and heat preservation film also respectively contains a matrix resin and an additive.

5. The agricultural greenhouse heat insulation and heat preservation film according to claim 4, characterized in that: The matrix resin includes at least one of polyethylene, nylon, polyvinyl alcohol, polypropylene, ethylene propylene diene monomer rubber, CTC resin, maleic anhydride.

6. The heat insulation and heat preservation film for agricultural greenhouses according to claim 4, characterized in that: The additive includes at least one of a lubricant, a light stabilizer, an antioxidant, a solubilizer, a coupling agent.

7. A method for preparing a heat-insulating and heat-preserving film, comprising the following steps: The premixes of the heat insulation layer, the light conversion layer, and the heat preservation layer are subjected to three - layer co - extrusion to obtain the agricultural greenhouse heat insulation and heat preservation film according to any one of claims 1 - 6.

8. The application of the agricultural greenhouse heat insulation and heat preservation film according to any one of claims 1 - 6 in an agricultural greenhouse.

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